USOO9726220B2

(12) United States Patent (10) Patent No.: US 9,726.220 B2

Kim (45) Date of Patent: Aug. 8, 2017
(54) THRUST FOIL AIR BEARING (58) Field of Classification Search
CPC ..................................................... F16C 177042
(71) Applicant: TNE KOREA CO., LTD., Daejeon See application file for complete search history.
(KR) (56) References Cited
(72) Inventor: Kyeong Su Kim, Daejeon (KR) U.S. PATENT DOCUMENTS
(73) Assignee: TNE KOREA CO., LTD., Daejeon 4,225, 196 A * 9/1980 Gray ..................... F16C 17,042
(KR) 384f121
5,248,205 A * 9/1993 Gu ........................ F16C 17,042
(*) Notice: Subject to any disclaimer, the term of this 384/106
patent is extended or adjusted under 35 (Continued)
U.S.C. 154(b) by 0 days. FOREIGN PATENT DOCUMENTS
(21) Appl. No.: 15/312,977 JP HO1-242816. A 9, 1989
JP 4041168 B2 1, 2008
(22) PCT Filed: Mar. 14, 2016 (Continued)
(86). PCT No.: PCT/KR2O16/OO2491 Primary Examiner — Thomas R. Hannon
(74) Attorney, Agent, or Firm — KORUS Patent, LLC;
S 371 (c)(1), Seong Il Jeong
(2) Date: Nov. 21, 2016
(57) ABSTRACT
(87) PCT Pub. No.: WO2016/1532.01 A thrust foil air bearing includes a bottom plate comprising
PCT Pub. Date: Sep. 29, 2016 a coupling portion protruding toward a rotating portion, an
intermediate plate arranged above an upper Surface of the
(65) Prior Publication Data bottom plate and comprising a bump foil that is elastically
US 2017/O191522 A1 Jul. 6, 2017 deformable and a first through-hole through which the
coupling portion passes, and a top plate arranged above an
(30) Foreign Application Priority Data upper Surface of the intermediate plate, facing the rotating
portion, and comprising a top foil arranged above the bump
Mar. 20, 2015 (KR) ........................ 10-2015-OO39031 foil and contactable with the rotating portion and a second
through-hole, through which the coupling portion passes,
(51) Int. Cl. formed at a position corresponding to the first through-hole.
FI6C32/06 (2006.01) The coupling portion couples the bottom plate, the interme
FI6C I7/04 (2006.01) diate plate, and the top plate to one another by passing
(Continued) through the first through-hole and the second through-hole.
(52) U.S. Cl. Thus, the thrust foil air bearing may be rapidly assembled
CPC ............ F16C 17/042 (2013.01); F16C 27/02
without a complicated process Such as welding.
(2013.01); F16C 43/02 (2013.01) 8 Claims, 9 Drawing Sheets
 US 9,726.220 B2
Page 2

(51) Int. Cl.

FI6C 27/02 (2006.01)
FI6C 43/02 (2006.01)
(56) References Cited
U.S. PATENT DOCUMENTS
6,158,892 A * 12/2000 Stewart ................. F16C 17,042
384/105
6,261,002 B1 7/2001 Ermilov et al.
7,108,488 B2 * 9/2006 Larue .................... F16C 17/024
384/103
9,033,579 B2* 5/2015 Yoshino ................ F16C 17,042
384/105

FOREIGN PATENT DOCUMENTS

KR 10-2001-00639 13 A T 2001
KR 10-2001-0063914. A T 2001
KR 10-0590 139 B1 6, 2006
* cited by examiner
U.S. Patent Aug. 8, 2017 Sheet 1 of 9 US 9,726.220 B2

FIG. 1

100
U.S. Patent Aug. 8, 2017 Sheet 2 of 9 US 9,726.220 B2
U.S. Patent Aug. 8, 2017 Sheet 3 of 9 US 9,726.220 B2

FIG. 4

S ss
sers SSSSSSSSSSSSAASSSSSSSSaaSNS SaaSS SaaS SaaSSSSSSS
U.S. Patent Aug. 8, 2017 Sheet 4 of 9 US 9,726.220 B2

FIG. 5
U.S. Patent Aug. 8, 2017 Sheet 5 Of 9 US 9,726.220 B2

FIG. 6
-C

100
U.S. Patent Aug. 8, 2017 Sheet 6 of 9 US 9,726.220 B2

FIG. 7
U.S. Patent Aug. 8, 2017 Sheet 7 Of 9 US 9,726.220 B2

FIG. 8
U.S. Patent Aug. 8, 2017 Sheet 8 of 9 US 9,726.220 B2

FIG. 9
U.S. Patent Aug. 8, 2017 Sheet 9 Of 9 US 9,726.220 B2

FIG 10

1 Ys - F

^-AA- 2
4. 3 2 (2) S
sC
 US 9,726,220 B2
1. 2
THRUST FOIL AR BEARING arranged above an upper Surface of the bottom plate and
comprising a bump foil that is elastically deformable and a
TECHNICAL FIELD first through-hole through which the coupling portion
passes, and a top plate arranged above an upper Surface of
The present invention relates to a thrust foil air bearing, the intermediate plate, facing the rotating portion, and
and more particularly, to a thrust foil air bearing which may comprising a top foil arranged above the bump foil and
be rapidly assembled without a complicated process such as contactable with the rotating portion and a second through
welding. hole, through which the coupling portion passes, formed at
a position corresponding to the first through-hole, in which
BACKGROUND ART 10 the coupling portion couples the bottom plate, the interme
diate plate, and the top plate to one another by passing
Airbearings Support a load by allowing a rotation shaft to through the first through-hole and the second through-hole.
float due to pressure of compressed air between the rotation The coupling portion of the bottom plate may be rotatable
shaft and a bearing. around the centerline between a locking position, where the
In the air bearing, when a gas having viscosity, Such as air, 15 coupling portion is detachably coupled to the intermediate
moves along with a movable surface and meets a stationary plate and the top plate, and a release position, where the
Surface, the gas is compressed and a pressure of air trapped coupling portion is separable from the intermediate plate and
between the movable surface and the stationary surface the top plate.
increases, thereby lifting the movable surface. The coupling portion may be previously bent in a shape
The air bearing may a thrust air bearing that Supports a of “I” or is bent in a shape of “1” after passing though the
load applied in a lengthwise direction of the rotation shaft or first through-hole and the second through-hole.
a journal air bearing that Supports a load applied in a radial The first through-hole and the second through-hole may
direction with respect to the rotation shaft. have a slot shape extending along a radial direction with
Another type of the thrust air bearing is a thrust foil air respect to the centerline.
bearing which uses a foil of a thin material to facilitate 25 Each of the bump foil and top foil may be plurally
formation of pressure and improve dynamic stability at high provided in a circumferential direction with respect to the
speed. centerline. The bump foil may have one end coupled to an
A thrust foil air bearing 1 according to the related art, as intermediate plate main body and another end formed in a
illustrated in FIG. 11, may include a bottom plate 2 that is wing shape and capable of performing a free motion, and the
a plate member coupled to a stationary portion S, a bump foil 30 top foil may have one end coupled to a top plate main body
3 arranged on an upper Surface of the bottom plate 2 and and another end formed in a wing shape and capable of
elastica deformable, and a top foil 4 arranged above the performing a free motion. The first through-hole may be
bump foil 3 and contactable with a rotating portion R. The formed between the other end of the bump foil and the
rotating portion R is coupled to a rotation shaft F rotating in intermediate plate main body, and the second through-hole
a preset rotation direction W around a centerline C. 35 may be formed between the other end of the top foil and the
In the thrust foil air bearing 1, the bump foil 3 and the top top plate main body.
foil 4 are coupled to the upper surface of the bottom plate 2 The stationary portion may include a bearing mounting
by welding. When the bump foil 3 and the top foil 4 are pin that is a protruding rod member, and each of the bottom
coupled to the bottom plate 2 by welding, the entire structure plate, the intermediate plate, and the top plate may include
of the bearing is simplified and initial product development 40 a bearing mounting hole through which the bearing mount
costs and mold manufacturing costs may be reduced. How ing pin passes.
ever, several series of manufacturing processes such as a The coupling portion of the bottom plate may be rotatable
press process and a welding process are required and manu around the centerline between a locking position, where the
facturing welding jigs and welding quality management are coupling portion is detachably coupled to the intermediate
needed. Thus, the thrust foil air bearing is disadvantageous 45 plate and the top plate, and a release position, where the
in terms of product price management and quality manage coupling portion is separable from he intermediate plate and
ment and thus is not suitable for mass production. the top plate. When the coupling portion is at the locking
position, the bearing mounting holes of the bottom plate, the
DETAILED DESCRIPTION OF THE INVENTIVE intermediate plate, and the top plate may be aligned in a line
CONCEPT 50 so that the bearing mounting pin passes through the bearing
mounting holes.
Technical Problem Each of the bearing mounting holes of the bottom plate,
the intermediate plate, and the top plate may be plurally
The present inventive concept provides a thrust foil air provided in the circumferential direction with respect to the
bearing having an improved structure that allows rapid 55 centerline, and arrangement patterns of the bearing mount
bearing assembling without a complicated process such as ing holes formed in the bottom plate, the intermediate plate,
welding. and the top plate may be different patterns according to a
position of use of the thrust foil air bearing.
Technical Solution The bottom plate, the intermediate plate, and the top plate
60 may have shapes which enable mass production by a press
According to an aspect of the present inventive concept, process.
there is provided a thrust foil air bearing for use in an
apparatus including a stationary portion and a rotating Advantageous Effects
portion relatively rotating around a centerline with respect to
the stationary portion includes a bottom plate coupled to the 65 According to the present inventive concept, a thrust foil
stationary portion and comprising a coupling portion pro air bearing includes: a bottom plate having a coupling
truding toward the rotating portion, an intermediate plate portion protruding toward a rotating portion, as a member
 US 9,726,220 B2
3 4
coupled to a stationary portion; a bump foil arranged above The rotating portion R and the stationary portion S are
an upper Surface of the bottom plate and elastically deform relative terms and have meanings regarding a relative rota
able; an intermediate plate having a first through-hole tion with respect to each other. The rotating portion R and
through which the coupling portion passes; a top plate the stationary portion S are interchangeable terms. In the
arranged above an upper Surface of the intermediate plate following description, however, it is assumed that the sta
facing the rotating portion and arranged above the bump foil tionary portion S denotes a fixed part in an absolute coor
and contactable with the rotating portion; and a top plate dinate system and the rotating portion R denotes a rotating
through which the coupling portion passes and having a part in the absolute coordinate system.
second through-hole at a position corresponding to the first The bottom plate 10, which is a circular disc member
through-hole, in which the coupling portion passes through 10 manufactured by press processing a metal thin plate, is
the first through-hole and the second through-hole coupling arranged above an upper Surface of the stationary portion S.
the bottom plate, the intermediate plate, and the top plate to The bottom plate 10 may include a bottom plate main body
one another. Accordingly, the bearing may be quickly 11, a coupling portion 12, and a bearing mounting hole 13.
assembled without a complicated process Such as welding. The bottom plate main body 11 is a circular disc portion
15 having a center on the centerline C and has a lower Surface
DESCRIPTION OF THE DRAWINGS arranged on the upper Surface of the stationary portion S.
A through-hole H having a center on the centerline C is
FIG. 1 is an assembled perspective view of a thrust foil air formed at the center of the bottom plate main body 11.
bearing according to an embodiment. The coupling portion 12, which is a portion previously
FIG. 2 is an exploded perspective view of the thrust foil bent in a shape of “”, protrudes from the bottom plate main
air bearing of FIG. 1, body 11 toward the rotating portion R.
FIG. 3 is a partially enlarged view of a portion A of the The coupling portion 12 is provided as a plurality of
thrust foil air bearing of FIG. 1. coupling portions spaced apart from one another at a preset
FIG. 4 is a cross-sectional view taken along a line B-B of interval in a circumferential direction with respect to the
the thrust foil air bearing of FIG. 1, 25 centerline C.
FIG. 5 is a partially enlarged view of a coupling portion The coupling portion 12 is located between an inner
of a bottom plate of FIG. 2. circumferential surface of the bottom plate main body 11
FIG. 6 is an exploded perspective view illustrating a state and an outer circumferential surface of the bottom plate
of use of the thrust foil air bearing of FIG. 1. main body 11, with a section of the “I” shape extending long
FIG. 7 is a plan view of a top plate of FIG. 2. 30 in a radial direction with respect to the centerline C.
FIG. 8 is a plan view of an intermediate plate of FIG. 2. In the present embodiment, the coupling portion 12 is
FIG. 9 is a plan view of a bottom plate of FIG. 2. located approximately halfway in the radial direction
FIG. 10 is a perspective view of a bearing according to between the inner circumferential surface of the bottom
another embodiment, in which an arrangement pattern of plate main body 11 and the outer circumferential surface of
bearing mounting holes is different from that of the bearing 35 the bottom plate main body 11.
of FIG. 1. The coupling portion 12 is formed by cutting and bending
FIG. 11 is a cross-sectional view of a foil air bearing the metal thin plate filling a cut-away portion 14 (see FIG.
according to the related art. 4) corresponding to the through-hole H of the bottom plate
main body 11, through a press process.
BEST MODE 40 A lower Surface of an upper portion of the coupling
portion 12 is spaced apart from an upper Surface of the
Hereinafter, the present inventive concept will be bottom plate main body 11 by a preset length T, as illustrated
described in detail by explaining preferred embodiments of in FIG. 5. In the present embodiment, the length T is about
the inventive concept with reference to the attached draw 0.05 mm to about 0.15 mm, which is greater than a sum of
1ngS. 45 thicknesses of the intermediate plate 20 and the top plate 30.
FIG. 1 is an assembled perspective view of a thrust foil air The coupling portion 12 couples the bottom plate 10, the
bearing 100 according to an embodiment. FIG. 2 is an intermediate plate 20, and the top plate 30 to be in a close
exploded perspective view of the thrust foil air bearing of contact with one another by passing through a first through
FIG. 1. FIG. 3 is a partially enlarged view of a portion A of hole 22 of the intermediate plate 20 and a second through
the thrust foil air bearing of FIG. 1. 50 hole 32 of the top plate 30, which are described below.
Referring to FIGS. 1 to 3, the thrust foil air bearing 100 The coupling portion 12 couples the bottom plate 10, the
according to the present embodiment, as an air bearing that intermediate plate 20, and the top plate 30 along the cen
Supports a load via pressure of compressed air, is a thrust terline C not to be separated from one another.
bearing usable for various apparatuses including a stationary In the present embodiment, the coupling portion 12 of the
portion S (see FIG. 6) and a rotating portion R (see FIG. 6) 55 bottom plate 10 is rotatably provided around the centerline
relatively rotating around a centerline C with respect to the C between a locking position where the coupling portion 12
stationary portion S. The thrust foil air bearing 100 may is detachably coupled to the intermediate plate 20 and the
include a bottom plate 10, an intermediate plate 20, and a top top plate 30 and a release position where the coupling
plate 30. portion 12 is separable from the intermediate plate 20 and
The stationary portion S and the rotating portion R are 60 the top plate 30.
circular disc members having a center on the centerline C. The bearing mounting hole 13, which is a hole through
The rotating portion R is coupled to a rotation shaft F (see which the bearing mounting pin P of the stationary portion
FIG. 6) rotating in a preset rotation direction W around the S passes, is provided as a plurality of bearing mounting
centerline C. A plurality of bearing mounting pins P which holes in the circumferential direction along an edge of the
are rod members having a circular section and protruding in 65 bottom plate main body 11.
a direction along the centerline C, are arranged on an upper The intermediate plate 20, which is a circular disc mem
surface of the stationary portion S. ber manufacturing by press processing a metal thin plate, is
 US 9,726,220 B2
5 6
arranged above an upper surface of the bottom plate 10 and The top plate 30, which is a circular disc member manu
includes an intermediate plate main body 21, the first factured by press processing a metal thin plate, is arranged
through-hole 22, a bearing mounting hole 23, and a bump above an upper surface of the intermediate plate 20 facing
foil 24. the rotating portion R. The top plate 30 may include a top
The intermediate plate main body 21, which is a circular 5 plate main body 31, the second through-hole 32, a bearing
disc portion having a center on the centerline C, has a lower mounting hole 33, and a top foil 34.
Surface arranged above the upper Surface of the bottom plate The bottom plate 10, the intermediate plate 20, and the top
main body 11. The intermediate plate main body 21 has the plate 30 may each be manufactured in the form of a metal
same diameter as the bottom plate main body 11. thin plate of the same material, but may have different
The through-hole H having a center on the centerline C is 10 thicknesses.
The top plate main body 31, which is a circular disc
formed at the center of the intermediate plate main body 21. portion having a center on the centerline C, has a lower
The through-hole H of the intermediate plate main body 21 Surface arranged above an upper Surface of the intermediate
has the same diameter as the through-hole H of the bottom plate main body 21. The top plate main body 31 has the same
plate main body 11. 15 diameter as the bottom plate main body 11.
The first through-hole 22, which is a hole having a slot The through-hole H is formed at the center of the top plate
shape extending along the radial direction with respect to the main body 31 with a center on the centerline C. The
centerline C, has a length and a width so that the coupling through-hole H of the top plate main body 31 has the same
portion 12 passes through the first through-hole 22. diameter as the through-hole H of the bottom plate main
The bearing mounting hole 23, which is a hole through 20 body 11.
which the bearing mounting pin P of the stationary portion The second through-hole 32, which is a hole having a slot
S passes, is provided as a plurality of bearing mounting shape extending long in the radial direction with respect to
holes in the circumferential direction along the edge of the the centerline C, has a length and a width so that the
intermediate plate main body 21. coupling portion 12 passes through the second through-hole
The bearing mounting hole 23 of the intermediate plate 20 25 32.
is located at a position corresponding to the bearing mount The second through-hole 32 is formed at a position
ing hole 13 of the bottom plate 10, and the bearing mounting corresponding to the first through-hole 22 and has the same
hole 23 and the bearing mounting hole 13 have the same length and width as the first through-hole 22.
diameter. The bearing mounting hole 33, which is a hole through
The bump foil 24, which is a portion having a trapezoidal 30 which the bearing mounting pin P of the stationary portion
planar shape has a wave form in which a plurality of crests S passes, is provided as a plurality of bearing mounting
and roots are alternately connected so as to be elastically holes in the circumferential direction along an edge of the
deformable in a vertical direction along the centerline C. top plate main body 31.
The bump foil 24, like the coupling portion 12, is formed The bearing mounting hole 33 of the top plate 30 is
by cutting and bending a metal thin plate filling a cut-away 35 formed at a position corresponding to the bearing mounting
portion 28, which is a hole of the intermediate plate main hole 13 of the bottom plate 10 and the bearing mounting hole
body 21, through a press process. 23 of the intermediate plate 20, and the bearing mounting
The bump foil 24 is provided as a plurality of bump foils hole 13, the bearing mounting hole 23, and the bearing
spaced apart at a preset interval from one another in the mounting hole 33 have the same diameter.
circumferential direction with respect to the centerline C. 40 In the present embodiment, the bearing mounting holes
In the bump foil 24, only one side 25 of two sides 25 and 13, 23, and 33 of the bottom plate 10, the intermediate plate
26, which are spaced apart from and facing each other in the 20, and the top plate 30 are arranged on a same imaginary
circumferential direction with respect to the centerline C, of circumference having a center on the centerline C.
four sides of a trapezoid, is coupled to the intermediate plate Arrangement patterns of the bearing mounting holes 13,
main body 21 whereas the other three sides are free ends. 45 23, and 33 on the bottom plate 10, the intermediate plate 20,
In the present embodiment, in the bump foil 24, based on and the top plate 30 may be incongruous patterns as illus
a flow of air with respect to the bump foil 24, only the side trated in FIG. 10, according to a position of use of the thrust
25 at the upstream side of the two sides spaced apart from foil air bearing. FIG. 10 illustrates a thrust foil air bearing
and facing each other in the circumferential direction with 200 according to another embodiment. The thrust foil air
respect to the centerline C is coupled to the intermediate 50 bearing 200 is mirror symmetric with the thrust foil air
plate main body 21. In other words, in the bump foil 24, bearing 100.
while only the side 25 at the upstream side is coupled to the In any one of the bottom plate 10, the intermediate plate
intermediate plate main body 21, the side 26 at the down 20, and the top plate 30 of the thrust foil air bearing 100, first
stream side is formed in a wing shape capable of performing and second arrangement angles C.1 and C2 between the
a free motion. 55 neighboring bearing mounting holes of the bearing mount
The bump foil 24 is formed long toward the downstream ing holes 13, 23, and 33 are asymmetrically formed to be
side along the circumferential direction with respect to the incongruous according to a position in the circumferential
centerline C, and includes a plurality of cut lines 27 spaced direction with respect to the centerline C. The first arrange
apart from one another in the radial direction with respect to ment angle C.1 is an acute angel less than 45° and has a value
the centerline C. 60 less than the second arrangement angle C2. In the present
In the present embodiment, the first through-hole 22 is embodiment, the first arrangement angle C.1 is 30° and the
formed around the side 26 at the downstream side of the two second arrangement angle C2 is 90°.
sides spaced apart from and facing each other in the cir Accordingly, as the arrangement patterns of a pair of the
cumferential direction with respect to the centerline C. The thrust foil air bearings 100 and 200 facing opposite end
cut-away portion 28 between the side 26 at the downstream 65 portions of the rotation shaft F are different from each other,
side of the bump foil 24 and the intermediate plate main an operator's error of mounting the bearings at opposite
body 21 may be the first through-hole 22. positions may be fundamentally prevented. In other words,
 US 9,726,220 B2
7 8
when the operator tries to mount the thrust foil air bearing coupling portion 12 at the release position is inserted into the
100 at a position where the thrust foil air bearing 200 is to first through-hole 22 and the second through-hole 32 of the
be mounted, the bearing mounting pins P are not inserted intermediate plate 20 and the top plate 30.
into the bearing mounting holes 13, 23, and 33. In the above state in which the coupling portion 12 passes
The top foil 34, which is a portion having a trapezoidal through the first through-hole 22 and the second through
planar shape, is arranged above the bump foil 24 and is hole 32, the bottom plate 10 is rotated counterclockwise with
contactable with the rotating portion R. respect to the intermediate plate 20 and the top plate 30, the
The top foil 34 is provided as a plurality of top foils coupling portion 12 is rotated to the locking position and
spaced apart from one another at a preset interval in the thus an end portion of the shape “L” of the coupling portion
circumferential direction with respect to the centerline C. 10 12 is detachably coupled to the top plate main body 31 and
The top foil 34 has a position and size corresponding to the intermediate plate main body 21, as illustrated in FIGS.
the bump foil 24. 3 and 4. In this state, the bearing mounting holes 13, 23, and
The top foil 34, like the bump foil 24, is formed by cutting 33 of the bottom plate 10, the intermediate plate 20, and the
and bending a metal thin plate filling a cut-away portion 37. top plate 30 are aligned in a line.
which is a hole of the top plate main body 31, through a 15 Finally, the thrust foil air bearing 100 having the bottom
press process. plate 10, the intermediate plate 20, and the top plate 30
In the top foil 34, only one side 35 of two sides 35 and 36, coupled to one another is moved to the upper Surface of the
which are spaced apart from and facing each other in the stationary portion S, and lowered such that the bearing
circumferential direction with respect to the centerline C, of mounting pins P of the stationary portion S are inserted into
four sides of a trapezoid, is coupled to the top plate main the bearing mounting holes 13, 23, and 33. After finishing
body 31, whereas the other three sides are free ends. the thrust foil air bearing 100 not to be separated from the
In the present embodiment, in the top foil 34, based on a bearing mounting pins P, the assembly and mounting of the
flow of air with respect to the top foil 34, only the side 35 thrust foil air bearing 100 are completed.
at the upstream side of the two sides spaced apart from and The thrust foil air bearing 100 configured as above
facing each other in the circumferential direction with 25 includes: the bottom plate 10 coupled to the stationary
respect to the centerline C is coupled to the top plate main portion S and having the coupling portion 12 protruding
body 31. In other words, in the top foil 34, while only the toward the rotating portion R; the intermediate plate 20
side 35 at the upstream side is coupled to the top plate main having the bump foil 24 arranged above the upper Surface of
body 31, the side 36 at the downstream side is formed in a the bottom plate 10 and elastically deformable and the first
wing shape capable of performing a free motion. 30 through-hole 22 through which the coupling portion 12
In the present embodiment, the second through-hole 32 is passes; and the top plate 30 arranged above the upper Surface
formed around the side 36 at the downstream side of the two of the intermediate plate 20 and facing the rotating portion
sides spaced apart from and facing each other in the cir R, and having the top foil 34 arranged above the bump foil
cumferential direction with respect to the centerline C. The 24 and contactable with the rotating portion R and the
cut-away portion 37 between the side 36 at the downstream 35 second through-hole 32, through which the coupling portion
side of the top foil 34 and the top plate main body 31 may 12 passes, formed at a position corresponding to the first
be the second through-hole 32. through-hole 22. Since the bottom plate 10, the intermediate
When the coupling portion 12 of the bottom plate 10 is at plate 20, and the top plate 30 are coupled to one another with
the locking position, the bearing mounting holes 13, 23, and the coupling portion 12 passing through the first through
33 of the bottom plate 10, the intermediate plate 20, and the 40 hole 22 and the second through-hole 32, the bearing may be
top plate 30 are arranged in a line so that the bearing quickly assembled without a complicated process Such as
mounting pins P pass therethrough. However, when the welding.
coupling portion 12 of the bottom plate 10 is at the release In the thrust foil air bearing 100, since the coupling
position, the bearing mounting hole 13 and the bearing portion 12 of the bottom plate 10 is rotatable around the
mounting holes 23 and 33 are not aligned in a line. 45 centerline C between the locking position where the cou
The bearing mounting pins P couples the bottom plate 10, pling portion 12 is detachably coupled to the intermediate
the intermediate plate 20, and the top plate 30 by allowing plate 20 and the top plate 30 and the release position where
the bottom plate 10, the intermediate plate 20, and the top the coupling portion 12 is separable from the intermediate
plate 30 to slide on an imaginary plane crossing the center plate 20 and the top plate 30, and the top plate 30, the bottom
line C and not to be slidably separated from one another. 50 plate 10, the intermediate plate 20, and the top plate 30 may
Also, the bearing mounting pins P prevent the coupling be coupled to one another by a simple manipulation of
portion 12 from unintentionally being rotated to the release relatively rotating the bottom plate 10 with respect to the
position. intermediate plate 20.
In the following description, a method of assembling and Furthermore, in the thrust foil air bearing 100, since the
mounting the thrust foil air bearing 100 having the above 55 coupling portion 12 is previously bent in the shape of “1”,
structure is described. the coupling portion 12 may be moved to the locking
First, the intermediate plate 20 and the top plate 30 are position by a simple manipulation of relatively rotating the
prepared to overlap each other Such that the bearing mount bottom plate 10 with respect to the intermediate plate 20 and
ing hole 23 of the intermediate plate 20 and the bearing the top plate 30.
mounting hole 33 of the top plate 30 are aligned in a line. In 60 In the thrust foil air bearing 100, since the first through
this state, the first through-hole 22 of the intermediate plate hole 22 and the second to through-hole 32 have a slot shape
20 and the second through-hole 32 of the top plate 30 are extending long in the radial direction with respect to the
aligned in a line. centerline C, by forming the coupling portion 12 long in the
Next, the intermediate plate 20 and the top plate 30 radial direction with respect to the centerline C, an area
overlapped with each other are moved over the upper 65 where the coupling portion 12 contacts the upper Surface of
surface of the bottom plate 10. The intermediate plate 20 and the top plate main body 31 is increased so that a coupling
the top plate 30 approach the bottom plate such that the force of the coupling portion 12 may be increased, and the
 US 9,726,220 B2
9 10
position of the coupling portion 12 may be easily selected on one for each, at least any one of the bottom plate 10, the
an imaginary line in the radial direction with respect to the intermediate plate 20, and the top plate 30 may be mounted
centerline C. two or more for each.
Furthermore, in the thrust foil air bearing 100, the bump In the present embodiment, although the arrangement
foil 24 and the top foil 4 each are plurally provided in the patterns of the bearing mounting holes 13, 23, and 33 in the
circumferential direction with respect to the centerline C, bottom plate 10, the intermediate plate 20, and is the top
and the bump foil 24 has one end coupled to the intermediate plate 30 are adjusted by changing the arrangement angles C.1
plate main body 21 and the other end formed in a wing shape and C2 formed by the neighboring bearing mounting holes
capable of performing a free motion, and the top foil 4 has 13, 23, and 33, the arrangement patterns may be adjusted by
one end coupled to the top plate main body 31 and the other 10 separately changing the distance from the centerline C to
end formed in a wing shape capable of performing a free each of the bearing mounting holes 13, 23, and 33.
motion, the first through-hole 22 is naturally formed While the present inventive concept has been particularly
between the other end of the bump foil 24 and the interme shown and described with reference to preferred embodi
ments using specific terminologies, the embodiments and
diate plate main body 21 without forming a separated 15 terminologies should be considered in descriptive sense only
through-hole, and the second through-hole 32 is naturally and not for purposes of limitation. Therefore, it will be
formed between the other end of the top foil 34 and the top understood by those of ordinary skill in the art that various
plate main body 31. changes in form and details may be made therein without
Since the stationary portion Sincludes the bearing mount departing from the spirit and scope of the present inventive
ing pins P that are protruding rod members and the bottom concept as defined by the following claims.
plate 10, the intermediate plate 20, and the top plate 30 What is claimed is:
include the bearing mounting holes 13, 23, and 33 through 1. A thrust foil air bearing for use in an apparatus
which the bearing mounting pins P pass, the thrust foil air comprising a stationary portion and a rotating portion rela
bearing 100 may be conveniently mounted on the stationary tively rotating around a centerline with respect to the sta
portion S by using the bearing mounting pins P that are 25 tionary portion, the thrust foil air bearing comprising:
easily obtained and have large structural strength. a bottom plate coupled to the stationary portion and
Furthermore, in the thrust foil air bearing 100, since the comprising a coupling to portion protruding toward the
coupling portion 12 of the bottom plate 10 is rotatable rotating portion;
around the centerline C between the locking position where an intermediate plate arranged above an upper Surface of
the coupling portion 12 is detachably coupled to the inter 30 the bottom plate and comprising a bump foil that is
mediate plate 20 and the top plate 30 and the release position elastically deformable and a first through-hole through
where the coupling portion 12 is separable from the inter which the coupling portion passes; and
mediate plate 20 and the top plate 30, and when the coupling a top plate arranged above an upper Surface of the
portion 12 is at the locking position, the bearing mounting intermediate plate, facing the rotating portion, and
holes 13, 23, and 33 of the bottom plate 10, the intermediate 35 comprising a top foil arranged above the bump foil and
plate 20, and the top plate 30 are aligned in a line so that the contactable with the rotating portion and a second
bearing mounting pins P may pass through the bearing through-hole, through which the coupling portion
mounting holes 13, 23, and 33, by inserting the bearing passes, formed at a position corresponding to the first
mounting pins Pinto the bearing mounting holes 13, 23, and through-hole,
33, the bottom plate 10, the intermediate plate 20, and the 40 wherein the coupling portion couples the bottom plate, the
top plate 30 are coupled to one another on the imaginary intermediate plate, and the top plate to one another by
plane crossing the centerline C not to be slidably separated passing through the first through-hole and the second
from one another, and further, the coupling portion 12 is through-hole.
prevented from unintentionally being rotated to the release 2. The thrust foil air bearing of claim 1, wherein the
position. 45 coupling portion of the bottom plate is rotatable around the
In the thrust foil air bearing 100, since the arrangement centerline between a locking position, where the coupling
patterns of the bearing mounting holes 13, 23, and 33 portion is detachably coupled to the intermediate plate and
respectively formed in the bottom plate 10, the intermediate the top plate, and a release position, where the coupling
plate 20, and the top plate 30 are incongruous according to portion is separable from the intermediate plate and the top
the position of use of the thrust foil air bearing, when a pair 50 plate.
of the thrust foil air bearings 100 and 200 are mounted 3. The thrust foil air bearing of claim 2, wherein the
facing the two rotating portions R coupled to the opposite coupling portion is previously bent in a shape of “I” or is
end portions of the rotation shaft F, an operator's error of bent in a shape of “1” after passing though the first through
mounting the bearings at opposite positions may be funda hole and the second through-hole.
mentally prevented. 55 4. The thrust foil air bearing of claim 1, wherein the first
Furthermore, since the bottom plate 10, the intermediate through-hole and the second through-hole have a slot shape
plate 20, and the top plate 30 all have shapes that are quickly extending along a radial direction with respect to the cen
formed by a press process, the thrust foil air bearing 100 is terline.
Suitable for mass production, compared to a method using 5. The thrust foil air bearing of claim 1, wherein each of
welding, for example. 60 the bump foil and top foil is plurally provided in a circum
In the present embodiment, although the coupling portion ferential direction with respect to the centerline,
12 is previously bent in a shape of “”, the coupling portion the bump foil has one end coupled to an intermediate plate
12 may initially have a shape of '-' and then is plastically main body and another end formed in a wing shape and
deformed to be bent in the shape of “1” after passing through capable of performing a free motion, and the top foil
the first through-hole 22 and the second through-hole 32. 65 has one end coupled to a top plate main body and
In the present embodiment, although the bottom plate 10, another end formed in a wing shape and capable of
the intermediate plate to 20, and the top plate 30 are mounted performing a free motion, and
 US 9,726,220 B2
11 12
the first through-hole is formed between the other end of
the bump foil and the intermediate plate main body, and
the second through-hole is formed between the other
end of the top foil and the top plate main body.
6. The thrust foil air bearing of claim 1, wherein the
stationary portion comprises a bearing mounting pin that is
a protruding rod member, and
each of the bottom plate, the intermediate plate, and the
top plate comprises a bearing mounting hole through
which the bearing mounting pin passes. 10
7. The thrust foil air bearing of claim 6, wherein the
coupling portion of the bottom plate is rotatable around the
centerline between a locking position, where the coupling
portion is detachably coupled to the intermediate plate and
the top plate, and a release position, where the coupling 15
portion is separable from the intermediate plate and the top
plate, and
when the coupling portion is at the locking position, the
bearing mounting holes of the bottom plate, the inter
mediate plate, and the top plate are aligned in a line so
that the bearing mounting pin passes through the bear
ing mounting holes.
8. The thrust foil air bearing of claim 6, wherein each of
the bearing mounting holes of the bottom plate, the inter
mediate plate, and the top plate are plurally provided in the 25
circumferential direction with respect to the centerline, and
arrangement patterns of the bearing mounting holes
formed in the bottom plate, the intermediate plate, and
the top plate are different patterns according to a
position of use of the thrust foil air bearing. 30
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